Hydraulically operated apparatus for mechanical splitting of rock and the like

ABSTRACT

A wedge member has a front end and diverges in direction rearwardly therefrom. The wedge member is hydraulically displaceable in longitudinal direction and has a pair of opposite outer surfaces. A pair of spreading members which are fixed with respect to the longitudinal displacement of the wedge member, overlie the outer surfaces thereof in engagement with them so that they spread radially when the wedge member is displaced forwardly. Mating tongues and grooves are provided in the wedge member and the spreading members and matingly interengage when the wedge member is rearwardly displaced.

[ Feb. 12, 1974 Darda HYDRAULICALLY OPERATED 2,225,852 12/1940 Acordi 299 23 APPARATUS FOR MECHANICAL 3,572,840 3/1971 Fletcher 299/23 SPLITTING OF ROCK AND THE LIKE FOREIGN PATENTS OR APPLICATIONS [76] Inventor: Helmut Darda, [m Ta], 7712 263,759 9/1913 Germany 299/23 Blumberg/Baden, Germany Primary ExaminerWerner I-I. Schroeder [22] Filed 1972 Attorney, Agent, or FirmMichael S. Striker App]. No.: 215,791

[30] Foreign Application Priority Data Jan. 13, 1971 Germany P 21 01 353.6

July 30, 1971 Germany P 21 38 071.2

[52] US. Cl. 299/23 [51] Int. Cl. E2lc 37/04 [58] Field of Search 299/20, 21, 22, 23

[56] References Cited UNITED STATES PATENTS 2,328,661 9/1943 Maloney 299/23 3,488,093 1/1970 Darda 299/22 3,558,191 1/1971 Fletcher et al 299/23 [5 7] ABSTRACT A wedge member has a front end and diverges in direction rearwardly therefrom. The wedge member is hydraulically displaceable in longitudinal direction and has a pair of opposite outer surfaces. A pair of spreading members which are fixed with respect to the longitudinal displacement of the wedge member, overlie the outer surfaces thereof in engagement with them so that they spread radially when the wedge member is displaced forwardly. Mating tongues and grooves are provided in the wedge member and the spreading members and matingly interengage when the wedge member is rearwardly displaced.

17 Claims, 34 Drawing Figures PAIENIEDF W Q 3.791.698

SHEETZHFK PATENTED 3' 791 698 sum u .UF- 3 PAIENIED FEB 1 21914 sum 6 OF 8 PATENTEDFEB 1 21914 31791 .698

SHEU 7 BF 8 v BACKGROUND OF THE INVENTION The present invention relates generally to an apparatus for mechanically splitting rocks and other materials, and more particularly to a hydraulically operated apparatus of this type.

Basically, apparatus of the type here under discussion is already known. Generally speaking such apparatus utilizes a high pressure cylinder and piston unit with the piston of which there is connected a longitudinally displaceable wedge member. Flanking the wedge member in engagement therewith are spreading members or jaws which are inserted into a cavity in the rock, a bore hole or the like, whereupon the wedge member is advanced forwardly spreading the spreading members apart and causing the rock to crack. A device of this general type is for instance disclosed in German allowed application No. 1,249,194 to which reference may be had for general background information.

Devices of this type are relatively readily employable for manual operation, that is they can be transported and handheld by a single operator. They are capable of producing splitting forces on the order of 300 tons and more of pressure, that is forces which are directed into the rock or similar material to be split and which thus effect splitting of the rock or removal of rock chunkswithout any need for explosives. The spreading members or jaws have diameters which are only on the order of 40 mm despite the large specific pressure which they can transmit to the rock, and this makes it possible to utilize such devices within relatively small gaps in the rock, for instance bore holes which need be very little larger than the 40 mm diameter and which thus can be produced inexpensively and simply.

Such devices have been found highly advantageous but they have encountered one difficulty, namely if used for splitting of reinforced concrete. In this case the splitting of the concrete itself initially requires a large force at a small stroke or displacement of the wedge member, and for driving the split chunks of concrete apart a larger stroke at lesser force is necessary in order to separate and release from the chunks of concrete the iron rods or similar elements which are used for reinforcing purposes. This problem has never been satisfactorily solved with the apparatus known from the art. In fact, a similar problem which also still awaits solution is to be found in circumstances where natural rock is being processed and where the chunks of rock which have already been split off the matrix are to be transported away with simple means. To make this possible, it is necessary that the gap produced with the apparatus be made wide enough to permit ropes or cables to be passed around the split-off chunk of rock so that the latter can be dragged or hoisted away.

These problems could basically be solved with a very long wedge member whose wedge surfaces conically taper forwardly under a small angle and over the entire length of the wedge member. Because the transverse lift of the spreading members would be proportional to the forward displacement of the wedge member, the spreading members could be driven far apart because of the long stroke of the wedge member. However, an apparatus so constructed would have to have large dimensions and, inasmuch as it is intended to be used for manual handling this is not practical because the apparatus could not longer be handled only by a single operator and thus would not be usable in actual practice.

SUMMARY OF THE INVENTION It is, accordingly, a general object of the present invention to overcome the disadvantages of the prior art.

More particularly it is an object of the present invention to provide an apparatus of the type here under discussion which is relatively compact and can readily be handled by a single operator, and whose spreading members can be spread apart farther than this is possible with the apparatuses known from the prior art.

In pursuance of these objects, and of others which will become apparent hereafter, one feature of the invention resides in an apparatus of the character hereindescribed which in its non-inventive aspects resembles the apparatus disclosed in the aforementioned German allowed application. According to the present invention, however, the novel apparatus additionally comprises a wedge member having a front end and diverging in direction rearwardly therefrom, with this wedge member being adapted for longitudinal displacement and having a pair of opposite outer surfaces each of which is an abutment with an overlying spreading member of a pair of such spreading members, with these spreading members being fixed longitudinally with reference to the wedge member so that they do not share the longitudinal advancement thereof but, in response to such longitudinal advancement, spread radially. There is further provided longitudinally extending mating tongue and groove means on at least two of the aforementioned members, matingly interengaging when the wedge member is rearwardly displaced.

I have found that the spreading members or jaws can be driven apart radially still farther than would otherwise be possible when the longitudinally extending tongue and groove means are provided, becuase these assure that in the starting position -that is with the wedge member retractedthe unit composed of the wedge member and the starting members will have a very small cross-section whereas in the end position that is with the wedge member forwardly displacedit will have a rather large cross-section. The provision of the tongue and groove means according to the present invention has a result that the contacting glide surfaces of the wedge member and the spreading members that is their respective surface areas are smaller in the operated position, that is the position in which the wedge member is forwardly displaced, than in the starting or rest position, so that given the same resistance the specific surface pressures would be greater. However, because at the time the wedge member is in its operated position the rock or other material has already been split, the resistance to be overcome is substantially smaller than that at the beginning of the operation of the device, so that the above feature does not constitute a disadvantage.

According to one feature of the invention, the longitudinally that is axially extending grooves of the tongue and groove means may be provided in the glide surfaces of the intermediate and/or rearward portions of the wedge member, and the mating tongues or ribs of the tongue and groove means may be provided in the corresponding portions of the spreading members, with the tongues and grooves providing contacting glide surface portions. With such a wedge member construction, the leading or forward end with the conically tapering glide surfaces thereof can be made longer --by comparison with wedge members of the type known from the art and given the same angle of taperwithout having to increase the overall cross-section of the unit and thereby having to require larger apertures in the rock for its insertion. The reason is that the unit is strengthened in its rearward region by the tongues which extend into the grooves.

In the starting position the conical glide surfaces of the wedge member drive the jaws or spreading members radially apart in known manner, that is in the manner which is disclosed in the aforementioned allowed German application. However, the effective crosssection of the wedge member in its thickest region is greater with respect to the wedge members known from the art, and thus the spreading members are driven farther apart than was heretofore known. The specific surface pressure is greater as compared with the apparatus known from the prior art, when the portion of the wedge member which is provided with grooves enters between the conically converging glide surfaces of the spreading members. However, this is not disadvantageous because at this time the surrounding rock has already been split and the resistance to be overcome is now substantially less than before, as has been explained above. At this time it is, on the contrary, more important that the already split rock be driven farther apart in order to completely separate it.

Of course, it will be appreciated that the interengaging tongues and grooves also provide for an improved guidance of the wedge member with respect to the spreading members. According to a further embodiment of the invention the glide surfaces of the grooves provided on the wedge member, and the tongues or ribs provided on the spreading members, may extend in parallelism with the longitudinal axes of the respective members and merge directly into the conically tapering glide surfaces at the forward or front end of the wedge member or the spreading members, respectively. Such a construction is particularly suitable for an apparatus in which the remaining glide surfaces of the wedge member and of the spreading members, that is the glide surfaces in the intermediate and rearward portions thereof, extend in parallelism with the longitudinal axes of the respective members.

However, according to a further concept of the invention, the glide surfaces of the wedge member and of the spreading members may also conically converge in forward direction over the entire length of the respective members. In this case the glide surfaces of the grooves provided in the wedge member, and the ribs provided on the spreading members are advantageously made to conically converge in forward direction in the rearward portions of the respective members, and to extend in axial parallelism in the intermediate portions of the respective members, whereas in the forward portions they will merge into conical glide surfaces provided on the wedge member and the spreading members, respectively.

Still another embodiment of the invention provides for the glide surfaces of the spreading members and of the wedge member to extend in axial parallelism with the longitudinal axes of the respective members at least in the intermediate portions thereof, and the glide surfaces of the grooves and of the ribs to conically taper in forward direction in such a manner that the grooves in the wedge member form a constriction in the intermediate portion of the wedge member which constriction merges into the thickest part of the wedge member. In this arrangement the spreading members are radially spread simultaneously at their forward portions and at their rearward or intermediate portions when the wedge member is advanced in forward direction.

A further construction according to the present invention makes it possible to maintain the desired small overall cross-sectional dimensions of the apparatus and to maintain the high force which can be transmitted therewith, while yet assuring an even stronger radial expansion and consequently even greater widening of the crack which has been produced in the rock. According to this concept, the spreading members extend axially forwardly beyond the front end of the wedge member when the latter is in its rearward position, and where they so extend they are provided with ribs and grooves which have a scissor-like interengagement and whose facing surface portions are configurated as glide surfaces for the glide surfaces provided on the wedge member. This means that the axially extending tongues and grooves are provided in the forward portion of the longer spreading members, whereas in the previously discussed embodiments they are provided in the intermediate and/or rearward portions of the spreading members and the wedge member. It should be noted, however, that it is possible to combine the two concepts with one another if the wedge member is provided at least in its intermediate portion with glide surfaces which extend in parallelism with its longitudinal axes. In this case the wedge member will be provided in its intermediate portion with grooves whose glide surface portions conically converge in the forward direction and into which correspondingly configurated tongues or ribs extend which are provided on the spreading members. Here, again, the spreading members will be spread apart simultaneously both at their front portion and at their rear portion.

If a still stronger expansion or spreading -and consequent widening of a gap produced in the rockis desired at the front portion of the unit, then the wedge member may be provided in its rearward portion with slide members which do not extend in parallelism with this longitudinal axis, but which instead conically converge in forward direction. It is advantageous that these glide surfaces merge smoothly and without any bend into the glide surfaces of the grooves proviced in the intermediate portion. In the embodiments mentioned just above it is desirable that the tip or front end of the wedge member not be sharp but instead be blunted or rounded, to avoid the possibility that as it enters between the scissor-like inter-engaging tongues and grooves of the spreading members, it might become wedged or skewed with reference to them. In other words, the front end of the wedge member should have a blunter angle of inclination than that which is defined by the other cooperating glide surfaces.

It is pointed out that the present invention has advantages beyond the obvious ones of affording better expansion and spreading. In addition, it provides for a better guidance and support both of the wedge member and of the spreading members. Furthermore, an automatic aligning of the spreading members with reference to one another can be achieved and the spreading members be appropriately guided back into their starting position when the wedge member is retracted to its which does not readily wear, at least in the region of strong friction or high surface pressures. Advantageously these surfaces are coated entirely or partially with a layer of a suitable hard metal.

The embodiment mentioned where portions of the spreading members extend forwardly beyond the front end of the wedge member, has the additional advantage that the front end of the wedge member is protected by these portions even during the forward advancement of the wedge member. If necessary or desired, the portions of the spreading members can be extended forwardly to such an extent that the front end of the wedge member will remain located between the spreading members and protected by them, even when the wedge member is fully advanced in forward direction. This prevents the relatively readily damaged front end of the wedge member from contacting the bottom of a bore hole or the like, or generally contacting the surrounding rock, which could result in damage to it or to portions of the slide surfaces in the region of the front end. If it is merely desired to obtain such a protection action it is evidently not necessary that the forwardly extending portions of the spreading members be provided with tongues and grooves which engage in scissor-like manner, as discussed earlier, but they can simply be extended forwardly beyond the front end of the wedge member without having such tongues and grooves. In fact, they can contact one another with glide surfaces which extend in parallelism with the longitudinal axes of the respective members.

It goes without saying, of course, that in the various embodiments herein the location of the tongues and grooves can be exchanged, that is grooves can be provided in the spreading members and tongues on the wedge member, or vice versa, without in any way effecting the inventive concept.

The invention also contemplates the possibility of having the spreading members connected axially so that they move simultaneously in axial direction, but have freedom of relative displacement in transverse direction, such connection preferably being provided in the region of the portions which extend forwardly beyond the front end of the wedge member. This measure prevents the spreading member from becoming displaced with reference to one another if they are subject to unequal loads. The spreading members are connected fixedly with the cylinder block of the unit, that is with the cylinder block of the hydraulic cylinder and piston unit which effects displacement of the wedge member, so that they cannot move in axial direction under normal circumstances. However, if the spreading members are subject to unequal loading there is the possibility that forces might be transmitted via the cylinder block and the piston which could bend or kink the piston rod and/or the upper end of the wedge memher with reference to the central longitudinal axes of the unit.

If the gap between split-apart chunks of rock which has been produced with the operation of the novel apparatus is still not sufficiently large, for instance to permit complete separation of a split-off chunk of rock or proper handling of the same, then auxiliary elements may be provided which increase the cross-section of the unit composed of the wedge member and the spreading members. Such auxiliary elements are known from the art but have the disadvantage that when the wedge member of the prior-art apparatus is advanced forwardly, the auxiliary elements tend to yield laterally or in rearward direction. The present invention aims to overcome this disadvantage by providing auxiliary elements which are provided at their forward ends, that is those which are initially inserted into the bore hole, with projections such as ribs, beads or the like which extend normal to the longitudinal axis of the respective auxiliary member and which engage in corresponding recesses provided at the front end of the spreading members themselves, whereas the rear ends of the auxiliary elements are provided with portions which in substantially U-shaped manner embrace the unit. These projections alone prevent axial displacement of the auxiliary elements with reference to the unit, and the embracing at the rear ends of the auxiliary elements provides for retention against lateral shifting.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view of one embodiment of the invention;

FIGS. 2-4 are respective radial sections taken on lines IIII, IIIIII and IV-IV of FIG. 1;

FIG. 3a is a radial section corresponding to that shown in FIG. 3 but illustrating a slightly different embodiment;

FIG. 5 is a view similar to FIG. 1 but of another embodiment of the invention;

FIGS. 6-10 are respective radial sections taken on lines VI-VI, VII-VII, VIII-VIII, IXIX and X-X of FIG. 5;

FIG. 1 1 is a view similar to FIG. 5 illustrating another embodiment of the invention;

FIGS. 12-14 are respective radial sections taken on lines XII-XII, XIIIXIII, and XIVXIV of FIG. 11;

FIG. 15 is a view similar to FIG. 11, showing still a further embodiment with the wedge member retracted;

FIGS. 16-18 are radial sections taken on lines XVI- -XVI, XVIIXVII, and XVIIIXVIII of FIG. 15;

FIG. 17a is a radial section analogous to the section of FIG. 17 but showing a slightly different embodiment;

FIG. 19 is an end view of FIG. 15 a seen in the direction of the arrow XIX;

FIG. 20 is a view similar to FIG. 15 of another embodiment of the invention;

FIGS. 21-24 are respective radial sections taken on lines XXI-XXI, XXII-XXII, XXIIIXXIII and XXIV-XXIV of FIG. 20;

FIG. 25 is a view similar to FIG. 12 illustrating still at additional embodiment of the invention;

FIGS. 26-27 are radial sections taken on lines XXVI- -XXVI and XXVIIXXVII of FIG. 25;

FIG. 28 is a view similar to FIG. 25 showing still a further embodiment of the invention;

FIGS. 29-30 are radial sections taken on lines XXIX- XXIX, and XXX-XXX of FIG. 28;

FIG. 31 is an enlarged partial view of the lower end of FIG. 28, on line XXXIXXXI thereof; and

FIG. 32 is a partially sectioned side view of yet an additional embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail it is pointed out that the embodiments which have been illustrated in the FIGS. 1-14 thereof are particularly suitable for use with the general type of apparatus which has been disclosed in the aforementioned allowed German application. However, they can also be used in other general type of apparatus which is capable of reciprocating the wedging member, and the same is true of the other embodiments.

In the drawing, reference numeral 1 designates a wedging member which, as just pointed out, is to be moved forwardly to operative position and retracted to rest or withdrawn position, by a non-illustrated hydraulically acted piston of the apparatus. Spreading members 2, which are to be inserted into a bore hole or the like in rock, are fixedly connected with the cylinder block of the apparatus, so that they cannot move axially when the wedging member moves in that manner.

As the drawing shows, the wedging member and the spreading members are provided at their forward end portions with conically converging guide surfaces 1a and 2a, respectively, with the glide surfaces 2a of the spreading members 2 being provided with a layer or surfacing of hard metal which has been illustrated in shaded lines and is provided for the purposes discussed earlier.

In the intermediate and rearward region the glide surfaces lb and 2b of the members 1 and 2, respectively, extend in parallelism with the longitudinal axes of the respective members. A reference to FIGS. 3 and 4 will show that in this region the opposite sides of the glide member 1 are provided with axially extending grooves of depth C, whereas the spreading member 2 are provided with similarly axially extending ribs or tongues which engage in the grooves 1c. The grooves 10 have axially parallel surfaces 1d and the tongues 20 have similar axially parallel surfaces 2d, with the surfaces 1d and 2d facing and contacting one another and acting with reference to one another as glide surfaces, that is they perform the functions which are the same as the functions of the surfaces lb and 2b.

FIG. 4 clearly shows that the cross-section of the member 1 in the region of the end portions 2e of the members 2 corresponds in surface area to the radial section of FIG. 3. The latter, considered in conjunction with FIG. I, clearly shows the advantage to be obtained with the present invention. It will be clear that in order for the members 2 to be able to withstand the forces resulting when rock is to be split, without undergoing damage or destruction, they must have a certain minimum cross-section. In the conventional apparatus of the type here under discussion, the conical glide surfaces la and 2a terminate at the line A-A which has been shown in FIG. 1; if that were not the case, given the same bore-hole diameter and thus cross-section of the apparatus to be inserted into them, the crosssection of the members 2 would be excessively weakened in the intermediate and rearward portions thereof.

However, by resorting to the present invention the surfaces 10 and 2a can be extended to the line B-B of FIG. 1, because the cross-section in this region is increased by the inwardly projecting tongue 2c, with the result that by comparison with the prior art and with the member 2 advanced to operating position, the members 2 can be driven apart by the additional stroke length 2xC, without requiring that larger-cross section members 2 and therefore larger dimensioned bore holes be utilized.

FIG. 3a shows that the grooves 2c and the tongues 10' can be reversed in their locations, being provided on the members 2' and 1, respectively, without departing in any sense from the present invention.

Coming to the embodiment illustrated in FIGS. 5-10, it will be seen that here the glide or wedge member is identified with reference numeral 3 and has glide surfaces 30 which conically converge in forward direction over substantially the entire length of the member 3. Similarly, the members 4 are provided with correspondingly conically converging surfaces 4a. The member 3 is provided with axial grooves 30 corresponding to those of the member 1 in FIGS. l-4, having glide surfaces 3d which in the intermediate portion D extend in axial parallelism with the longitudinal axis of the member 3, whereas in the rearward portion E they taper conically. The members 4 are provided with tongues 4c which extend into the grooves 3c and have glide surfaces whose arrangement as to axial parallelism and conical taper corresponds to that of the grooves 30. With this embodiment, the glide surfaces 4d will, in the initial or starting position, contact the glide surfaces 3d of the grooves 3c, as a comparison of the radial sections of FIGS. 8 and 9 clearly shows. The member 3 is so strongly widened in the region of the section line VIIIVIII that the tongues 40 are com pletely received in the grooves 30.

Still another embodiment is illustrated in FIGS. 11-14 where the wedge member is identified with reference numeral 5, having glide surfaces similar to those shown in FIG. 1. The glide surfaces 5a of the member 5 conically converge in the forward portion of the member, and in the rearward portion they extend in axial parallelism and are identified with reference numeral 5b. The glide surfaces 6a and 6b of the spreading member 6 are correspondingly configurated. On both sides of the member 5, there are provided axially extending grooves 5c which extend from the rearward end of the center or middle of the member 5, having glide surfaces 5d which conically taper to the section line XIIIXIII. The corresponding glide surfaces 6d of the tongues 6c are similarly configurated.

A reference to FIG. 11 indicates that the conically converging glide surfaces 5d form a constriction Se in the region of the section XIIIXIII, and that in forward direction the constriction again widens to the width of the member 5. Thus, when the member 5 is advanced forwardly, the members 6 will be simultaneously spread apart both in the intermediate portion as well as in the forward portion. In this embodiment, the relatively strong specific surface pressures will already begin at the initiation of the operating stroke of the member 5, and for this reason hard metal coatings are provided on the glide surfaces 6d of the tongues 6c in the aforementioned region, as indicated in shading lines. Similar coatings are provided on the glide surfaces 66 as in analogy to the embodiment of FIG. 1.

In the embodiment illustrated in FIG. 15, the wedge member 7 is provided at its front end with conically converging glide surfaces 7a which merge into glide surfaces 7b at the rearward portion, with the glide surfaces 7b extending in parallelism with the longitudinal axis of the member 7. The configuration of the glide surfaces on the spreading members 8, identified with reference numerals 8a and 8b, corresponds to that on the member 7. The embodiments in FIGS. -24 differ from the preceding embodiments insofar as the front portions of the spreading members 8 extend forwardly beyond the front end of the wedge member 7 when the latter is in its retracted or rest position. These extended from portions 8e are provided with tongues 8f and grooves which engage in scissor-like fashion, and the glide surfaces 8a are extended into glide surfaces 80 on the one hand, and on the other hand into the glide surfaces 8d.

It will be appreciated that when the wedge member 7 is advanced in forward direction, the glide surfaces 7a of the member 7 initially contact the glide surfaces 8a of the members 8 driving the same apart. When the member 7 has been advanced to such an extent that its front tip 70 is located at the level of the section line XVII-XVII, glide surfaces 7a will contact on the one hand the glide surfaces 8c and on the other hand glide surfaces 8d, with the result that the members 8 are further spread apart by an amount which corresponds to the depth of the groove and the height of the tongue 8f.

To prevent clamping and retention of the member 7 against further advancement when it comes initially into contact with the glide surfaces 8a, the tip 70 of the member 7 is either rounded or generally blunted.

FIG. 19 shows that the edges 8g of the tongue 8f are bevelled to simplify the retraction of the members 8 to their starting position when the member 7 is retracted to its own rest position.

The broken lines indicate that the glide surfaces 7a, 8a, 8c and 8d are provided with a wear-resistant surface, preferably with a hard metallic coating, in order to prevent the wear and seizing which otherwise occurs at the high specific surface pressures which act in operation.

The cross-sectional configuration is illustrated in FIGS. 1649 of generally polygonal contour. However, it can also be of circular contour as illustrated in FIG.

17a, which indicates that the members 8' may be of semi-circular cross-section at the level of the section line XVII-XVII. At the level of the section line XVIII- -XVIII, they are configurated in the same manner as indicated in FIGS. 18 and 19.

The embodiment illustrated in FIGS. 20-24 is similar below the section line XXII-XXII of FIG. 20 to the embodiment shown in FIG. 15, which means that the radial sections of FIGS. 22, 23 and 24 are comparable to the sections of FIGS. 16, 17 and 18. It will be seen that in this embodiment the difference is in the intermediate and rearward portions. In the intermediate portion the wedge member 9 is provided with glide surfaces 9b extending in parallelism with its longitudinal axis and provided with grooves 9f whose glide surfaces 92 converge conically in forward direction. Correspondingly configurated tongues ltig extend into these grooves and have glide surfaces 19h which contact the glide surfaces 9e. The grooves 9f form a constriction 93 in the intermediate portion of the member 9, with the constriction (see FIG. 20) widening into the wider front portion of the member 9 in an arcuate contour. In the intermediate region, the spreading members are driven apart to an equal extent as in the forward portion, a consideration which is particularly important for certain applications, for instance when natural rock is to be split and driven apart.

The tip 9c of the member 9 is provided in this embodiment also with a blunted or rounded end, that is it has a less sharp angle than that defined by the glide surfaces 9a for the reasons indicated earlier.

A further embodiment of the invention is illustrated in FIGS. 25-27, having a wedge member 11 and spreading members 12 and corresponding in essence to the embodiment illustrated in FIG. 1. Here, however, an auxiliary element 13 is provided which serves to cooperate with the remainder of the members when rock has been split to the maximum extent possible by the spreading apart of the members 12, but the split thus formed must be widened still further. In this case the apparatus is retracted from the bore hole and one or two of the elements 13 are connected to it. FIGS. 25 and 27 show that the members 12 are provided at their front end with radially extending bores or openings 12a, whereas the members 13 (one shown) are provided with projections 13a which can extend into these bores 120. At the rear end the members 13 are provided with U-shaped or bent portions 13b which embrace the apparatus in the region of the section line XXVIXXVI. Thus connected with the apparatus, the member or members 13 are reinserted into the bore hole with the apparatus. The projection 13a in cooperation with the portion 13b prevents lateral or axial displacement of the member 13 with respect to the apparatus when the wedge member 11 is again advanced in forward direction (having of course been retracted before the apparatus was previously moved from the bore hole), so that the gap can now be widened.

Coming now to the embodiment illustrated in FIGS. 283l, it will be seen that the projections 13a and bores can also be replaced with ribs 16a provided at the front end of an element 16 which corresponds to the element 13 of the preceding embodiment. These ribs 16a, which are located opposite one another, engage in corresponding grooves 15a provided on spreading members 15, although the relationship can of course be reversed. In either case, however, the element 16 again embraces the respectively associated spreading member 15 in the same manner as in the preceding embodiment, as is clearly illustrated in FIG. 30. The rib 16a and grooves 15a, clearly shown in FIG. 31, prevent axial displacement of the element 16 with respect to the apparatus which is composed of the spreading members 15 and the associated wedge member 14 (of course aside from the cylinder and piston unit which is again not illustrated). The rear end of the element 16 is provided with U-shaped portions 16b which embrace the apparatus in the region of the section line XXIX- XXIX in order to prevent lateral displacement of the element 16 with reference to the apparatus in operation of the latter.

There is, finally the embodiment illustrated in FIG. 32. Here, spreading members are identified with reference numeral 18 and are .of such length as to extend forwardly beyond a wedge member 17 even when the latter is in its operative (advanced) position. Those portions of the members 18 which extend forwardly beyond the member 17 are connected with one another by means of a pin or similar element 18a which is fixed to one of these portions and extends into an opening 18b of the other portion.

The purpose of this connection is, of course, to prevent relative longitudinal displacement of the members 18 in the event unequal forces should act upon them. Thus, the embodiment of FIG. 32 has the same purpose as the embodiments of FIGS. 25-31.

In FIG. 32, the pin 18a is freely slidable in the opening 18b, because the members 18 must be capable of transversely spreading apart from one another. Under same circumstances it is, however, conceivable that members 18 or their forwardly extending portions might be sufficiently yieldable (e.g. spring steel) to permit pin 18a as an analogous element to be fixedly connected with both of the members 18 while yet preserving the necessary freedom of lateral spreading of these members due to their yieldable character.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in an apparatus for splitting rocks and analogous materials, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristic of the generic or specific aspects of this invention and, therefore, such adaptation should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In an apparatus of the character described, in combination, a pair of elongated spreading members having mutually facing inner first glide surfaces; a wedge member having two mutually opposing outer second glide surfaces and being insertable between said spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while the respective first and second glide surfaces abut each other with attendant spreading of said spreading members; and mating groove and tongue means provided on the respective first and second glide surfaces so as to engage each other in the retracted position, and disengage from each other in the advanced position of said wedge member.

2. In an apparatus as defined in claim 1, said wedge member and said spreading members each having a forward portion, a rearward portion and an intermediate portion; and wherein said tongue and groove means are provided in at least one of said intermediate and rear ward portions of said spreading and wedge members.

3. In an apparatus as defined in claim 2, said forward portions having a conical taper, and wherein said spreading and wedge each have a longitudinal axis and said tongue and groove means extend in parallelism with said axes and into said forward portions.

4. In an apparatus as defined in claim 2, said tongue and groove means being provided in both said intermediate and rearward portions, and wherein said spreading and wedge members each have a longitudinal axis and said tongue and groove means extend in parallelism with the longitudinal axes of said spreading and wedge members, respectively, in said intermediate portions and have cooperating contact surfaces which converge conically in said rearward portions of said spreading and wedge members.

5. In an apparatus as defined in claim 2, wherein said spreading and wedge members each have a longitudinal axis and said first and second glide surfaces extend in parallelism with said axes at least in said intermediate portions, and said groove and tongue means conically converge in direction to said forward portion with attendant formation of a constriction in said wedge member.

6. In an apparatus as defined in claim 5, said wedge member having at said rearward portion thereof respective forwardly converging glide surfaces which merge into said grooves in said intermediate portion.

7. In an apparatus of the character described, in combination, a first spreading member having an inner first glide surface; a second spreading member having an inner second glide surface; a wedge member having a front end and two mutually opposing diverging outer third glide surfaces and being insertable between said first and said second spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while said third glide surfaces abut said first and said second glide surfaces, respectively, with attendant spreading of said spreading members; and wherein said first and said second spreading members each comprise a front portion projecting beyond said front end of said wedge member in the retracted position of the latter, and matingly interengaging groove and rib means in said front portion.

8. In an apparatus as defined in claim 7, wherein said front end of said wedge member is rounded.

9. In an apparatus as defined in claim 7, wherein said front end of said wedge member is blunt.

10. In an apparatus as defined in claim 7, said rib means having longitudinally extending bevelled edges.

11. In an apparatus as defined in claim 1, and wherein at least some of said glide surfaces are at least in part provided with a wear-resistant coating.

12. In an apparatus as defined in claim 11, wherein said glide surfaces are provided with said coating in the region of the forward portions of the respective sliding and wedge members.

13. In an apparatus as defined in claim 11, wherein additional glide surfaces are provided on said tongue means, and wherein said coating is provided on said glide surfaces of said tongue means.

14. In an apparatus of the character described, in combination, a pair of elongated spreading members having mutually facing inner first glide surfaces; a wedge member having an axis, a front end and two mutually opposing diverging outer second glide surfaces and being insertable between said spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while the respective first and second glide surfaces abut each other, with attendant spreading of said spreading members; and mating groove and tongue means provided on the respective first and second glide surfaces so as to engage each other in the retracted position, and disengage from each other in the advanced position of said wedge member, said spreading members each comprising a front portion which extends forwardly beyond said front end of said wedge member, and slide surface portions on said front portions which overlie and abut each other and extend in planes paralleling the longitudinal axis of said wedge member when the same is in said retracted position.

15. In an apparatus as defined in claim 14, said spreading members being connected against relative axial displacement but having freedom of relative lateral displacement.

16. In an apparatus of the character described, in combination, a pair of elongated spreading members having mutually facing inner first glide surfaces; a wedge member having two mutually opposing outer second glide surfaces and being insertable between said spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while the respective first and second glide surfaces abut each other with attendant spreading of said spreading members; mating groove and tongue means provided on the respective first and second glide surfaces so as to engage each other in the retracted position, and disengage from each other in the advanced position of said wedge member; and at least one auxiliary member adapted to overlie an outer side of a respective one of said spreading members extending longitudinally thereof, said auxiliary member having a front end portion and a rear end portion, and said auxiliary member and said spreading members being provided with cooperating engaging portions for releasably connecting said auxiliary member with a respective spreading member at said front and rear end portions so as to prevent displacement of said auxiliary member relative to the respective spreading member.

17. In an apparatus of the character described, in combination, a pair of elongated spreading members having mutually facing inner first glide surfaces; a wedge member having an axis, a front end and two mutually opposing diverging outer second glide surfaces and being insertable between said spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while the respective first and second glide surfaces abut each other, with attendant spreading of said spreading members; and mating groove and tongue means provided on the respective first and second glide surfaces so as to engage each other in the retracted position, and disengage from each other in the advanced position of said wedge member, said spreading members each comprising a front portion which extends forwardly beyond said first end of said wedge member when the same is in said retracted position; and matingly interengaging connecting means on said front portions for preventing said spreading members from mutual displacement in the longitudinal direction of said wedge member while permitting their spreading displacement transversely to said longitudinal direction. 

1. In an apparatus of the character described, in combination, a pair of elongated spreading members having mutually facing inner first glide surfaces; a wedge member having two mutually opposing outer second glide surfaces and being insertable between said spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while the respective first and second glide surfaces abut each other with attendant spreading of said spreading members; and mating groove and tongue means provided on the respective first and second glide surfaces so as to engage each other in the retracted position, and disengage from each other in the advanced position of said wedge member.
 2. In an apparatus as defined in claim 1, said wedge member and said spreading members each having a forward portion, a rearward portion and an intermediate portion; and wherein said tongue and groove means are provided in at least one of said intermediate and rearward portions of said spreading and wedge members.
 3. In an apparatus as defined in claim 2, said forward portions having a conical taper, and wherein said spreading and wedge each have a longitudinal axis and said tongue and groove means extend in parallelism with said axeS and into said forward portions.
 4. In an apparatus as defined in claim 2, said tongue and groove means being provided in both said intermediate and rearward portions, and wherein said spreading and wedge members each have a longitudinal axis and said tongue and groove means extend in parallelism with the longitudinal axes of said spreading and wedge members, respectively, in said intermediate portions and have cooperating contact surfaces which converge conically in said rearward portions of said spreading and wedge members.
 5. In an apparatus as defined in claim 2, wherein said spreading and wedge members each have a longitudinal axis and said first and second glide surfaces extend in parallelism with said axes at least in said intermediate portions, and said groove and tongue means conically converge in direction to said forward portion with attendant formation of a constriction in said wedge member.
 6. In an apparatus as defined in claim 5, said wedge member having at said rearward portion thereof respective forwardly converging glide surfaces which merge into said grooves in said intermediate portion.
 7. In an apparatus of the character described, in combination, a first spreading member having an inner first glide surface; a second spreading member having an inner second glide surface; a wedge member having a front end and two mutually opposing diverging outer third glide surfaces and being insertable between said first and said second spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while said third glide surfaces abut said first and said second glide surfaces, respectively, with attendant spreading of said spreading members; and wherein said first and said second spreading members each comprise a front portion projecting beyond said front end of said wedge member in the retracted position of the latter, and matingly interengaging groove and rib means in said front portion.
 8. In an apparatus as defined in claim 7, wherein said front end of said wedge member is rounded.
 9. In an apparatus as defined in claim 7, wherein said front end of said wedge member is blunt.
 10. In an apparatus as defined in claim 7, said rib means having longitudinally extending bevelled edges.
 11. In an apparatus as defined in claim 1, and wherein at least some of said glide surfaces are at least in part provided with a wear-resistant coating.
 12. In an apparatus as defined in claim 11, wherein said glide surfaces are provided with said coating in the region of the forward portions of the respective sliding and wedge members.
 13. In an apparatus as defined in claim 11, wherein additional glide surfaces are provided on said tongue means, and wherein said coating is provided on said glide surfaces of said tongue means.
 14. In an apparatus of the character described, in combination, a pair of elongated spreading members having mutually facing inner first glide surfaces; a wedge member having an axis, a front end and two mutually opposing diverging outer second glide surfaces and being insertable between said spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while the respective first and second glide surfaces abut each other, with attendant spreading of said spreading members; and mating groove and tongue means provided on the respective first and second glide surfaces so as to engage each other in the retracted position, and disengage from each other in the advanced position of said wedge member, said spreading members each comprising a front portion which extends forwardly beyond said front end of said wedge member, and slide surface portions on said front portions which overlie and abut each other and extend in planes paralleling the longitudinal axis of said wedge member when the same is in said retracted position.
 15. In an apparatus as defined in claim 14, said spreading members being conneCted against relative axial displacement but having freedom of relative lateral displacement.
 16. In an apparatus of the character described, in combination, a pair of elongated spreading members having mutually facing inner first glide surfaces; a wedge member having two mutually opposing outer second glide surfaces and being insertable between said spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while the respective first and second glide surfaces abut each other with attendant spreading of said spreading members; mating groove and tongue means provided on the respective first and second glide surfaces so as to engage each other in the retracted position, and disengage from each other in the advanced position of said wedge member; and at least one auxiliary member adapted to overlie an outer side of a respective one of said spreading members extending longitudinally thereof, said auxiliary member having a front end portion and a rear end portion, and said auxiliary member and said spreading members being provided with cooperating engaging portions for releasably connecting said auxiliary member with a respective spreading member at said front and rear end portions so as to prevent displacement of said auxiliary member relative to the respective spreading member.
 17. In an apparatus of the character described, in combination, a pair of elongated spreading members having mutually facing inner first glide surfaces; a wedge member having an axis, a front end and two mutually opposing diverging outer second glide surfaces and being insertable between said spreading members so as to be displaceable in relation to the same between a retracted and an advanced position while the respective first and second glide surfaces abut each other, with attendant spreading of said spreading members; and mating groove and tongue means provided on the respective first and second glide surfaces so as to engage each other in the retracted position, and disengage from each other in the advanced position of said wedge member, said spreading members each comprising a front portion which extends forwardly beyond said first end of said wedge member when the same is in said retracted position; and matingly interengaging connecting means on said front portions for preventing said spreading members from mutual displacement in the longitudinal direction of said wedge member while permitting their spreading displacement transversely to said longitudinal direction. 